Usefulness of an Automatic Quantitative Method for Measuring Regional Cerebral Blood Flow Using 99mTc Ethyl Cysteinate Dimer Brain Uptake Ratio

OBJECTIVES Improved brain uptake ratio (IBUR), employing (99m)Tc-ethyl cysteinate dimer ((99m)Tc-ECD), is an automatic non-invasive method for quantitatively measuring regional cerebral blood flow (rCBF). This method was developed by the reconstruction of the theory and linear regression equation, based on rCBF measurement by H2 (15)O positron emission tomography. Clarification of differences in rCBF values obtained by Patlak plot (PP) and IBUR method is important for clinical diagnosis during the transition period between these methods. Our purpose in this study was to demonstrate the relationship between rCBF values obtained by IBUR and PP methods and to evaluate the clinical applicability of IBUR method. METHODS The mean CBF (mCBF) and rCBF values in 15 patients were obtained using the IBUR method and compared with PP method values. RESULTS Overall, mCBF and rCBF values, obtained using these independent techniques, were found to be correlated (r=0.68). The mCBF values obtained by the IBUR method ranged from 18.9 to 44.9 ml/100g/min, whereas those obtained by the PP method ranged from 34.7 to 48.1 ml/100g/min. The rCBF values obtained by the IBUR method ranged from 16.3 to 60.2 ml/100g/min, whereas those obtained by the PP method were within the range of 26.7-58.8 ml/100g/min. CONCLUSION The ranges of mCBF and rCBF values, obtained by the IBUR method, were approximately 60% lower than those obtained by the PP method; therefore, this method can be useful for diagnosing lower flow area. Re-analysis of prior PP data, using the IBUR method, could be potentially useful for the clinical follow-up of rCBF.